You could probably guess from the assembling audience that the orchestra making its Barbican debut last night came from Milan. That many mink coats rarely congregate in a London concert hall.

A fired-up Maria Callas (Tyne Daly) is hectoring a student. “I don’t want it done like me, I want it done like Verdi!” “With music?” enquires the nervy pianist. “Yes,” she snaps, “With music: this isn’t a play.” Quite. What exactly is Terrence McNally’s Master Class? A classy version of “Tonight, Matthew, I’m going to be Maria Callas”? Yes, but no. There’s impersonation, but not of her singing.

When Riccardo Chailly (b 1953) left the Royal Concertgebouw for the Leipzig Gewandhaus, Richard Morrison said it was as if Bill Gates had ditched Microsoft for Aeroflot. The Gewandhaus has since become one of the lustiest of orchestral beasts in the world. Chailly and his orchestra make a rare appearance at the Barbican next Thursday and like all his previous visits it's likely to be a pretty unmissable event.